이미지 처리 속도를 높이기 위해 PHP 기능을 사용하는 방법은 무엇입니까?

$imgPath = 'path/to/image.jpg';
$newWidth = 800;
$newHeight = 600;

// 创建新的图像资源
$newImage = imagecreatetruecolor($newWidth, $newHeight);

// 从原始图像复制并调整大小
$sourceImage = imagecreatefromjpeg($imgPath);
imagecopyresampled($newImage, $sourceImage, 0, 0, 0, 0, $newWidth, $newHeight, imagesx($sourceImage), imagesy($sourceImage));

// 保存新图像
imagejpeg($newImage, 'path/to/newimage.jpg');

// 释放资源
imagedestroy($newImage);
imagedestroy($sourceImage);

$imgPath = 'path/to/image.jpg';

// 检查缓存是否存在
$cacheFile = 'path/to/cachedimage.jpg';
if (file_exists($cacheFile)) {
  // 如果缓存存在，直接输出缓存图像
  header('Content-Type: image/jpeg');
  readfile($cacheFile);
  exit;
}

// 如果缓存不存在，处理并保存新图像
$newWidth = 800;
$newHeight = 600;

$newImage = imagecreatetruecolor($newWidth, $newHeight);
$sourceImage = imagecreatefromjpeg($imgPath);
imagecopyresampled($newImage, $sourceImage, 0, 0, 0, 0, $newWidth, $newHeight, imagesx($sourceImage), imagesy($sourceImage));

// 保存新图像
imagejpeg($newImage, $cacheFile);

// 输出新图像
header('Content-Type: image/jpeg');
readfile($cacheFile);

// 释放资源
imagedestroy($newImage);
imagedestroy($sourceImage);

$images = ['path/to/image1.jpg', 'path/to/image2.jpg', 'path/to/image3.jpg'];

// 创建并发执行的进程数
$processCount = 4;

// 创建子进程
$processes = [];
for ($i = 0; $i < $processCount; $i++) {
  $processes[$i] = new swoole_process(function ($worker) use ($images, $i, $processCount) {
    for ($j = $i; $j < count($images); $j += $processCount) {
      // 处理图片
      // ...
    }
    $worker->exit();
  });
  $processes[$i]->start();
}

// 等待子进程执行完毕
foreach ($processes as $process) {
  swoole_process::wait();
}